A sensor network is composed of a great number of sensor nodes which are small, cheap, powered by a battery, and capable of wireless communicating and monitoring. These nodes are deployed densely in the monitored region, so as to monitor the physical environment. Wireless sensor network is a new research subject in the information technology, and has promising prospect in applications such as environmental monitoring, military affairs, territory security, traffic control, community security protection, forest fire prevention, and target location.
Because most sensor nodes are deployed in unattended region or opponent region, the security issue of the sensor network is especially acute. The sensor network is a data-centered data collecting platform, and establishing a safe infrastructure of authentication and key management in the sensor network is the basis for safe convergence, storage and access control of data. Presently, research on security technologies in the sensor network has got great breakthrough, and many security technologies for the sensor network have been proposed. The key management, as the basis of the sensor network security and the supporting technology for implementing secret communication of nodes and identity authentication between nodes, generally includes two stages: pre-distribution of key before the network deployment; and establishment of key and negotiation of session key after the network deployment. The authentication includes message authentication and identity authentication. The sensor network implements important functions, such as the routing list creation, network searching, software updating, time synchronization, and network management, based on broadcast. Because of the wireless and broadcast characteristics of the sensor network, the broadcast information may be tampered or be inserted with malicious information by attackers. In view of this, it is necessary to introduce the authentication mechanism for ensuring the legitimacy and the integrity of the broadcast information, and the broadcast information authentication technology is also the basis of the sensor network security. The identity authentication, as the basis of the computer network security and also the basis of the sensor network security, is used to authenticate the legitimacy and the validity of the identities of the two communication parties. As the core security mechanism, the key management and the authentication are indispensable for sensor network security solutions and are mutually supporting. Specifically, the authentication mechanism needs the key pre-distribution technology in the key management mechanism to provide pre-shared keys or initial keys, and the session key negotiation technology in the key management mechanism bases in turn on the result of the identity authentication, so that a basic sensor network security solution is able to be constructed only if the authentication mechanism and the key management mechanism work in coordination. However, the combining of the key management mechanism and the authentication mechanism is not fully considered in designing a sensor network at present, thus it is failed to provide complete secret communication service and authentication service for the sensor network, and there is still potential safety hazard in the sensor network.